School-slate



(No Model.)

P. O. RITCHIE.

SCHOOL SLATE.

No. 360,327. Patented Mar. 29, 1887.

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UNITED STATES I ATENT FFICE.

PETER O. RITCHIE, OF FREMONT, NEV YORK.

SCHOOL-SLATE.

SPECIFICATION forming part of Letters Patent No. 360,327, dated March 29, 1887.

A pplicntion filed June 10, 1886. Serial No. 204,747.

T 0 all whom it may concern:

Be it known that I, PETER O. RITCHIE, a citizen of the United States, residing at Tremont, in the county of New York, in the State of New York, have invented new and useful Improvements in Slates, of which the following is a specification.

The object of my invention is to provide a slate with a novel frame of a noiseless material, which is at the same time impervious to water or moisture, so that the frame does not become dirty and sticky as with ordinary woolen muffling-strips.

The general construction of my slate'frame is more fully pointed out in the following specification and claim, and illustrated in the accompanying drawings, in which Figure 1 represents a face View of a slate provided with a water-proof muftling-strip. Fig. 2 is a transverse section thereof in the plane 00 m, Fig. 1. Fig. 3 is a cross-section of the attaching frame.

Similar lettersindicate corresponding parts.

In the drawings, the letter A designates a piece of slate such as is ordinarily employed in the manufacture of slates, B is the mufflingstrip, and O is the attaching-frame.

The attaching-frame is made of thin sheet metal, which is bent so that it can be passed over the'edges of the slate, and it is provided in its length with numerous burrs or projections, c,which project inward toward the slate, and can be formed by depressing the material at selected points. The mufliing-strip consists of a long piece of a water-proof material, such as oil-cloth, rubber, and the like, and to secure the same to the edges of the slateits 1ongitudinal edges 1) b are introduced between the (No model.)

attaching-frame and the slate, and the attaching-frame is then pressed together upon the ac slate, whereby the muii'ling-strip is securely clamped all around its edges. The burrs con the attaching-frame penetrate the material of the inull'ling-strip and add greatly to the security of the fastening.

Heretofore muli'ling-strips have been made of llannel or other noiseless material, all of which are more or less liable to absorb moisture-for instance, when the slate is washed with a sponge moistened with wateratter which dust or dirt readily adheres to the muffiing-strip, and it becomes very unsightly and also sticky. This I avoid by making the muftling-strip ofa water-proofmaterial,which does not absorb the water which is used in cleaning 5 the slate, and therefore always presents a neat, bright, and clean appearance, while such a inufl'lingstrip is as durable as the ordinary strip.

\Vhat I claim as new, and desire to secure by Letters Patent, is-

The combination, with a slate, of the attaching-frame extending around the edges of the slate and embracing the same, burrs or projections in said frame, and a muftlingstrip over the attaching frame, the edges of which lie between the slate and the attaching-frame and are penetrated by the burrs or projections of the latter, substantially as shown and described.

In testimony whereof I have hereunto set my hand and seal in the presence of two subscribing witnesses.

PETER G. RITCHIE. [I.. s.]

\Vitnesses:

A. FABER DU FAUR, J r., W. HAUFF. 

